Laser lines (i.e., thin lines of laser light), are often used in the construction industry. Laser lines can mark where a saw will make its cut on a part so the part can be properly aligned to the saw. Also, horizontal level lines are used as an indicator to show when the correct height is achieved in the building of a foundation, wall or ceiling. Such horizontal level lines can also be formed by laser lines.
A laser line can be created by using either moving or non-moving components. A moving component, for example, a rotating polygon mirror, can scan a laser beam along a line. However, because it is expensive to use moving components, low cost laser line generator systems typically use non-moving components and, thus, do not scan a laser spot over a surface to form what is perceived as an image of a line. In a laser line generator system with non-moving components laser light forming the laser line results from light which is being emitted substantially simultaneously from a laser.
In a laser line generator system with non-moving components a laser line is often generated by introducing a cylindrical lens in the path of a collimated laser beam causing the beam to spread in the direction of the cylinder power and thus producing a line of light. A cylindrical lens is a lens with an optical power in one plane and no optical power in another plane. This approach works well when used with gas tube lasers because the output of a gas tube laser is collimated.
Laser diodes are much less costly and more rugged than gas tube lasers and because of this they are often used in the construction industry. Producing the same result with a laser diode, however, is a more difficult task because the output of a laser diode is not collimated. Instead, the laser beam provided by the laser diode diverges quite rapidly and the amount of divergences differ in two orthogonal directions. Thus, typical laser line generator systems use a laser diode 1 and two optical components--a collimator lens element 3 and an additional cylindrical lens element 5. (A cylindrical lens element has optical power in only one direction). Such a laser line generator system is illustrated in FIG. 1. The collimator lens 3 is placed in front of the laser diode 1 to first collimate the diverging laser beam emitted by the laser diode 1, producing a collimated beam of a small cross section. The cylindrical lens 5 then collects the collimated laser beam from the collimator lens 3 and diverges the collected light in one direction, forming a laser line 7. Because prior art laser line generator systems require two optical components in addition to a laser diode, such laser line generator systems are relatively bulky. In addition, manufacture and assembly of two optical components comprising the laser line generator system is relatively expensive.